A conventional crib for an infant has a main frame consisting of a headboard and a footboard that form the ends and two parallel sides, usually having vertical bars with openings between them. A horizontal mattress support is positioned within this main frame and consists of a rectangular spring frame and springs on which a mattress rests extending horizontally across the main frame. It is usually possible to secure the mattress support to the main frame at a variety of discrete vertical levels. Generally, it is desirable to position the mattress support at a low enough level with relation to the top of the crib sides so that there is no danger of the child falling out. However, the lower the mattress, the more difficult it is to attend to a child in the crib or to change the bedding. There is, therefore, no one mattress position that is both safe and convenient.
It should be noted that raising and lowering the mattress is a difficult and awkward task requiring far too much time and effort to permit the mattress to be raised whenever the child requires attention or the bedding is to be changed. Instead, a suitable compromise level must be selected in view of the size of the child, and the mattress remains in that position.
It has long been recognized that it would be highly desirable if it were possible to quickly and easily raise the mattress when attending to the child or changing the bedding and to then lower it again. A variety of mechanisms have been proposed for this purpose but, these mechanisms have, in general, been characterized by a variety of disadvantages including undesirable complexity and expense or difficulty of operation.
Most such mechanisms that have been proposed require that they be built into the crib as it is originally manufactured and are, therefore, not suitable for the large number of cribs currently in use. One important reason for the lack of adaptability of these mechanisms to existing cribs relates to the variety of constructions of the spring frames, some of which are tubular having radius corners while others are fabricated of right angle pieces that form sharp corners.
It is an objective of the present invention to provide an improved mechanism for raising and lowering the mattress of the crib that is of reduced complexity and expense but is, nevertheless, easily and conveniently operated. Another objective is to provide such mechanism that can be used with a wide variety of cribs of different sizes and having different spring frame configurations.